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Frogwatch[_2_] Frogwatch[_2_] is offline
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First recorded activity by BoatBanter: Nov 2008
Posts: 1,525
Default Bronze corrosion

On Sep 3, 10:15*am, wrote:
On Thu, 3 Sep 2009 07:07:08 -0700 (PDT), Frogwatch



wrote:
On Sep 3, 6:28*am, wrote:
On Wed, 2 Sep 2009 20:04:03 -0700 (PDT), Frogwatch


wrote:
About three years ago, I moved my sailboat to a slip in a real marina
for the first time ever. *I was surprised to see my shaft zinc go away
really fast. *Then I noticed the edges of the bronze prop were really
rough and brittle. *Uh-oh, *So, I needed to get her bottom painted
anyway so had her hauled, not an easy thing to do around here (no
facilities). *The bronze prop was a goner so I replaced it with a
PerfectPitch plastic prop that I like. *However, the bronze shaft
strut also looked corroded but was good enough to last awhile. *Now, I
have a diver check the zinc every 6 weeks.
So, I plan to haul her again soon and am thinking of replacing the
shaft strut.
Today, I dug out the old bronze prop whose blade edges were so
depleted of zinc that I could break off chunks of metal and examined
it. *It was only near the blade edges that it was wasted of zinc
except a thin veneer of corrosion all over. *The rest of it showed
good bronze when I used the dremel tool on it.
3 yrs ago when she was hauled, a small piece actually broke off near
the cutless bearing holder lip (not structural) causing me to think it
was wasted badly. *This experiment makes me not so sure that it is
bad. *I can only determine this by using the dremel all over the strut
when she is hauled. *Anybody have any experience with this?
Now, I can have a strut made but that will prob take forever, they
have to use the old one as a model and cast it. I will not be sailing
again till next year, no good.


Hmmmm.......I've got a well equipped machine shop, so, maybe I can
make a strut. *Maybe I can make a strut base from silicon bronze, make
a strut body from another piece bolted and brazed to base with a
cutless bearing holder brazed to that. *Thoughts?


Don't bother trying to fix your boat until the electrical problem at
the dock is fixed.


I will be moving but the boat manufacturer no longer exists (S2) and
its subsequent ancestor no longer has parts for 29 yr old boats. *So,
what do y'all think about my making a shaft strut?


You could probably make one in a machine shop. On the other hand, a
lot of boats were broken up for parts after hurricanes in the gulf
coast area. You might be able to find a used strut pretty cheaply and
save yourself some time and effort.

There are boat salvage/parts operations with websites.


Yes, a salvage one. Maybe I could even get an off-the-shelf one to
work if I make an adapter of G10 to put between the hull and strut to
adjust the angle and length.
Thanks